Humans venturing to sea have long waged a battle against barnacles and other fouling marine growth. Barnacles and other marine growth significantly reduce hull speed, reduce fuel efficiency and are highly destructive to both sail and power boats. They are also dangerous and can cause cuts and infections to boaters unfortunate enough not to respect their razor sharp shells.
There are products, such as copper (actually cuprous oxide or Cu2O) based antifouling paints, which can be applied to submerged components of a boat (i.e., components of the boat that are at least partly under water when the boat is docked or moored and provide an attractive habitat for marine organisms) to inhibit marine growth. However, some submerged components cannot tolerate copper based paint. For example, copper based paint cannot be applied to aluminum outboard engine and inboard/outboard drive components, such as outboard engine mounting brackets and inboard/outboard drive units, since the two dissimilar metals form a battery and severe electrolysis of the aluminum can occur, turning a strong metal component into aluminum oxide powder. When a boater makes the mistake of putting a copper based paint on an aluminum boat component, the outcome is an expensive lesson not soon forgotten.
As an alternative to copper based antifouling paints, marine paint manufacturers offer less effective tin based antifouling paints that are safe to use on aluminum. While tin based paints are better than nothing, they are vastly inferior antifouling agents to copper based paints. Copper based paint is effective in preventing virtually all marine growth from one to two years with very little maintenance. Moreover, after two years of continuous in the water use, often all that is required is a pressure wash and paint touch up and the copper based paint continues to be effective for another one or two years of service. Such is not the case with tin based paints. Submerged components painted with tin based paint are typically protected from marine growth for only two to three months before succumbing to some marine growth which, if left unchecked, will grow to complete coverage within six to twelve months. A typical solution is to haul the boat every two to three months and re-apply a fresh coat of the tin based paint to the components. However, such haul outs are both expensive and time consuming.
An alternative to tin based antifouling paints is addressed in U.S. Pat. No. 4,998,496, which describes surrounding the submerged portion of an inboard/outboard outdrive unit with a waterproof shroud and using an electric pump to empty the shroud of water, thereby keeping the submerged components from being in constant contact with water. Similarly, U.S. Pat. No. 4,282,822 describes placing an entire boat inside a floatable protective shroud. While these systems may work to a degree, they are expensive, complex, require an active pumping system, must be kept watertight and are very cumbersome to use. For example, the device described in U.S. Pat. No. 4,998,496 must be installed prior to storage of the boat and removed and stored prior to use of the boat. Moreover, these systems require frequent pumping for boats moored in all but the calmest of harbors. Frequent pumping requires the boat to have a battery charging system, which in turn requires the boat to be connected to grid power or an adequate solar charging system.
Another alternative to tin based antifouling paints is for the boater to periodically (e.g., monthly) scrub the submerged components or hire a dive service to do so, which is laborious and/or costly.
Still another alternative is to allow the marine growth to flourish unchecked on the submerged components, which can cause permanent damage to these components.
Accordingly, there is a need for an efficient and safe solution for inhibiting marine growth on the submerged components of a boat, particularly those that are incompatible with copper based paints.